Flood Risk Assessment for Urban Areas in North America
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D.J. Bader Flood Risk Assessment for urban areas in North America © AP Photo / David J. Phillip Flood Risk Assessment for urban areas in North America By D.J. Bader in partial fulfilment of the requirements for the degree of Bachelor of Science in Civil Engineering at the Delft University of Technology, Supervisor: dr. ir. S. van Vuren, TU Delft Secondary supervisor: dr. ir. B. Kolen, TU Delft ABSTRACT Floods are an increasing problem all over the world. Due to climate changes and socio-economic developments multiple areas are at risk. Flood risk is nowadays expressed as the global economic losses due to floods and these losses are raising. HKV and Deltares recognized this problem and started to develop a method to calculate flood risks. A Flood Risk Assessment Tool (FIAT) is used to calculate monetary values of flood risk. This is done by the apparent simple multiplication of exposure, vulnerability and hazard. This risk assessment is one of the steps of gaining knowledge about global flood risk and contributes to prevention of major disasters. In this Bachelor Thesis an extensive explanation about the procedure of a flood risk assessment for North America is included. The assessment can be performed in multiple ways. One can perform it by using the single land use method, but a multiple land use method as well. The explanation is mainly about the multiple land use method. Problems and difficulties are highlighted for future studies. Secondly a literature study is performed on elements that are also of importance in flood risk assessment. This study is performed for five cities: New Orleans, Los Angeles, Miami, New York City and Philadelphia. These studies have been investigated on multiple aspects to figure out which of those elements is most sensitive for the monetary value of the flood risk. Aspect taken in to account are: Risk, Population Density, Socio-Economic Development, Flash Flood Fatalities, Urban Planning, Flood Experience, Protection Standards by Scussolini et al. (2016) and “Real” Protection Standards. Protection levels seemed to be the most important input data for the Flood Impact Assessment Tool used in this flood risk assessment. It decreases the yearly expected damage with a factor ten. Data used by previous studies looked doubtful because of the equal character of all protection levels in the states of America and the source was vague. Some digging however showed that the protection standards aren’t equal at all. A further investigation on this element is suggested. Flood experience shouldn’t be underestimated, because governments in different cities show a trend. Most of the time governments go in to action when something happens. New Orleans and New York for example developed a plan after a hurricane came by. This wait-and-see attitude is a common habit in North America. PREFACE Hereby I present my Bachelor Thesis that I wrote in partially fulfilment of the requirements of the degree of Bachelor of Science in Civil Engineering. During this project I used my knowledge gained in the education on the Technical University of Delft. I liked the challenges that I had to face and despite multiple problems I liked how it all worked out. I want to thank my supervisors Saskia van Vuren and Bas Koolen for their feedback and support during the last eight weeks. They were available at any moment and always were willing to make time for my questions or my uncertainties. I would also like to thanks Jan Huizinga for his help with the software of QGIS and ArcGIS, with which I was struggling in the beginning. I really appreciate the time that he took out for me, a fantastic gesture! I have learned a lot that I can apply in further projects. I liked the challenge of this project and the experience gained will be of big help the future! D.J. Bader Delft, June 2016 CONTENTS 1 INTRODUCTION ....................................................................................................................................... 1 1.1 PROBLEM STATEMENT ........................................................................................................................ 1 1.2 OBJECTIVE ....................................................................................................................................... 2 1.3 STRUCTURE OF THE REPORT ................................................................................................................ 3 2 THEORETICAL BACKGROUND .................................................................................................................... 4 2.1 TYPES OF FLOODS .............................................................................................................................. 4 2.2.1 HAZARDS .................................................................................................................................. 5 2.2.2 EXPOSURE ................................................................................................................................ 5 2.2.3 VULNERABILITY .......................................................................................................................... 5 2.2.4 RISK ........................................................................................................................................ 5 2.3 DAMAGE CATEGORIES ........................................................................................................................ 6 2.4 LATEST DEVELOPMENTS ...................................................................................................................... 6 2.4.1 SOCIO-ECONOMIC DEVELOPMENT .................................................................................................. 6 2.4.2 CLIMATE CHANGES ..................................................................................................................... 7 3 PROCEDURE FLOOD RISK ASSESSMENT FOR NORTH AMERICA ........................................................................ 8 3.1 HAZARD ASSESSMENT......................................................................................................................... 8 3.2 EXPOSURE ASSESSMENT ..................................................................................................................... 9 3.3 VULNERABILITY ASSESSMENT ............................................................................................................... 9 3.4 RISK ASSESSMENT ........................................................................................................................... 11 3.5 DERIVING LAND USE MAPS ................................................................................................................. 12 3.6 IMPLEMENTATION IN FIAT ................................................................................................................... 13 4 RESULTS FLOOD RISK ASSESSMENT NORTH AMERICA ................................................................................ 15 5 FLOOD POLICY RESEARCH ...................................................................................................................... 18 5.1 VULNERABILITY FRAMEWORK ............................................................................................................. 18 5.2 PROTECTION LEVEL .......................................................................................................................... 19 5.3 FLOOD INSURANCE ........................................................................................................................... 21 5.4 PUBLIC AWARENESS ......................................................................................................................... 22 5.5 FLOOD FATALITIES ........................................................................................................................... 23 5.6 SOCIO-ECONOMIC DEVELOPMENT ....................................................................................................... 26 5.8 CLIMATE CHANGES .......................................................................................................................... 28 5.9 EMERGENCY MANAGEMENT ............................................................................................................... 29 5.10 OTHER ASPECTS ............................................................................................................................ 30 5.11 FLOOD ASSESSMENT ELEMENTS FICHE ............................................................................................. 30 5.11.1 READING GUIDE ..................................................................................................................... 32 5.11.2 NEW ORLEANS, LOUISIANA ....................................................................................................... 33 5.11.3 LOS ANGELES, CALIFORNIA ...................................................................................................... 37 5.11.4 NEW YORK CITY, NEW YORK..................................................................................................... 40 5.11.6 PHILADELPHIA, PENNSYLVANIA .................................................................................................. 45 5.11.7 INTEGRATED FLOOD ASSESSMENT ELEMENTS FICHE ...................................................................... 48 6 DISCUSSION ........................................................................................................................................ 49 7 CONCLUSION ......................................................................................................................................